Tài liệu FELINE DENTISTRY Oral Assessment, Treatment, and Preventative Care_1 pdf

Saliva from the parotid gland exits at a papilla in the alveolar mucosa, just caudal to the maxillary fourth premolar.. The bottom of the gingival sulcus in a periodontally exten-The max

FELINE DENTISTRY

Oral Assessment, Treatment, and Preventative Care

Edition fi rst published 2010

© 2010 Jan Bellows

Blackwell Publishing was acquired by John Wiley & Sons in

Febru-ary 2007 Blackwell’s publishing program has been merged with

Wiley’s global Scientifi c, Technical, and Medical business to form

Wiley-Blackwell.

Editorial Offi ce

2121 State Avenue, Ames, Iowa 50014-8300, USA

For details of our global editorial offi ces, for customer services, and

for information about how to apply for permission to reuse the

copyright material in this book, please see our website at www.

wiley.com/wiley-blackwell.

Authorization to photocopy items for internal or personal use, or

the internal or personal use of specifi c clients, is granted by

Black-well Publishing, provided that the base fee is paid directly to the

Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA

01923 For those organizations that have been granted a photocopy

license by CCC, a separate system of payments has been arranged

The fee codes for users of the Transactional Reporting Service are

ISBN-13: 978-0-8138-1613-5/2010.

Designations used by companies to distinguish their products are

often claimed as trademarks All brand names and product names

used in this book are trade names, service marks, trademarks or

registered trademarks of their respective owners The publisher is

not associated with any product or vendor mentioned in this book

This publication is designed to provide accurate and authoritative information in regard to the subject matter covered It is sold on the understanding that the publisher is not engaged in rendering professional services If professional advice or other expert assis- tance is required, the services of a competent professional should

Includes bibliographical references and index.

ISBN 978-0-8138-1613-5 (hardback : alk paper) 1 Veterinary dentistry 2 Cats–Diseases I Title.

Care–veterinary 4 Mouth Diseases–veterinary SF 867 B448f 2010]

636.8 ′ 08976–dc22 2009031848

A catalog record for this book is available from the U.S Library

of Congress.

Set in 9.5/12 pt Palatino by Toppan Best-set Premedia Limited Printed in Singapore

1 2010

Dedication

This text is dedicated to

Dr Colin E Harvey

Throughout his professional life, Dr Colin Harvey

has taught and mentored others while creating and

maintaining the foundation of veterinary dentistry in

the United States and around the world

Dr Harvey graduated from the School of Veterinary

Science at the University of Bristol, England, in 1966 He

completed an internship and residency in small animal

surgery at the University of Pennsylvania, receiving the

Diploma of the American College of Veterinary

Sur-geons in 1972

Dr Harvey is a diplomate of the American College of

Veterinary Surgeons (1972), member of the Organizing

Committee and charter diplomate of the American

Vet-erinary Dental College (AVDC, 1988) and the European

Veterinary Dental College (1998), and also a charter

dip-lomate of the European College of Veterinary Surgeons

(1993) He was section chief of Small Animal Surgery

(1974 – 80) and vice - chair of the Department of Clinical

Studies (1996 – 2002) and was the founding head of the

Dentistry and Oral Surgery Service at the University of

Pennsylvania (the fi rst dentistry and oral surgery service

to be established at a veterinary school in North

America)

Dr Harvey has received numerous university,

national, and international awards for excellence in

teaching, research, and clinical work He was elected a

fellow of the College of Physicians of Philadelphia in

1980 Dr Harvey has been a board member (1978 – 83) of

the Comparative Respiratory Society, secretary (1985 – 89) of the American Veterinary Dental Society, president (1990 – 92) and executive secretary (2002 – present) of the American Veterinary Dental College, cofounder (1985)

of the International Veterinary Ear Nose and Throat Association, charter fellow and secretary - treasurer (1987 – 89) of the Academy of Veterinary Dentistry, and director (1997 – present) of the Veterinary Oral Health Council

Dr Harvey was editor of the Journal of Veterinary Surgery from 1982 to 1987 and editor of the Journal of Veterinary Dentistry from 1994 to 2000 and has been a

reviewer or review board member for numerous other journals His publications include approximately 70 chapters in textbooks, 130 papers in peer - reviewed jour-nals, and over 100 abstracts and other papers on surgical and dental topics He has written, edited, or coedited

fi ve books on small animal surgery and dentistry

Dr Harvey ’ s research interests include veterinary and comparative periodontal disease (including compara-tive microbiology, standardization of periodontal scoring, and prevention and treatment); the interaction

of infectious oral diseases, particularly periodontal disease, with the rest of the body, specifi cally, distant organ and systemic effects; and the utility and effective-ness of antimicrobial drugs in the management of patients with oral diseases

Feline dentistry has been of special interest to Dr Harvey Much of what we know about feline dentistry today is largely due to his and his mentees ’ uncompro-mised research and discovery efforts

v

Chapter 5 Oral Pathology, 101

Section II Treatment, 149

Chapter 6 Equipment, 151

Chapter 7 Anesthesia, 169

Chapter 8 Treatment of Periodontal Disease, 181

Chapter 9 Treatment of Endodontic Disease, 196

Chapter 10 Treatment of Tooth Resorption, 222

Chapter 11 Treatment of Oropharyngeal Infl ammation, 242

Chapter 12 Treatment of Occlusion Disorders, 269

Chapter 13 Oral Trauma Surgery, 280

Chapter 14 Treatment of Oral Swellings/Tumors, 290

Section III Prevention, 297

Chapter 15 Plaque Control, 299

Index, 305

by the body ’ s own tissues for reasons that are still not clear, and our frustrations are heightened by the lack of success of restoring feline teeth undergoing resorption Squamous cell carcinoma is by far the most common feline oral neoplasm, benign or malignant; and it resists all standard treatments used in management of other malignancies When we add in that anesthesia is essen-tial for all feline dental procedures (lest our fi ngers be impaled by the needle - like, plaque - coated canine teeth) and that cats have such a little mouth compared with dogs, it is not surprising that there is some love - hate aspect to the relationship of veterinary dentists to cats The challenge is one to rise to, and the companionship cats offer makes it all worthwhile

A book dedicated to feline dentistry and related topics

is overdue I am pleased that Dr Bellows has found the time to pull the material together in a coherent format,

so that others may build upon the accumulated ence and knowledge that are described here Those deli-cate feline oral structures require all the skill and knowledge that we have and deserve our best efforts to ensure that we are not continuously restarting the steep - slope part of the learning curve

Colin E Harvey

Preface

Ah, Cats

What would veterinary dentistry be without them!

For sure, a lot simpler and less frustrating Even for

procedures so apparently “ simple ” as a tooth extraction,

the cat often has the last word, when we as veterinary

dentists hear that quiet but awful ‘ snick ’ that means that

a tooth root has fractured, leaving a root tip somewhere

down there …

Since the fi rst - reported mention of oral disease in cats

in the 1920s, a lot of progress has been made, but some

key knowledge is not yet available The immunological

function of the cat does not seem to obey the same rules

as rodents, dogs, and humans; and as a result,

immuno-logically based conditions such as stomatitis continue to

frustrate veterinary dentists Teeth in cats are attacked

Additionally, I acknowledge the American Veterinary Dental College (AVDC) in their efforts to “ get things right ” I have had the pleasure and honor of being a member and chairman of the college ’ s nomenclature committee since 2004, during which time the college has improved classifi cations for tooth resorption stages and types, fractures, periodontal disease, and many anatom-ical terms

I acknowledge and thank Dr Paul Pion, the originator

of the Veterinary Information Network (VIN) Dr Pion strives to improve the veterinary community on all levels Through the give and take on VIN ’ s message forums, we learn from each other I also thank Dr Pion for the use of his talented full - time graphic artist, Tamara Rees, who provided illustrations for the AVDC and this text

Finally, I can ’ t say enough about the publisher of this text, Wiley - Blackwell Working with Nancy Simmer-man, the Editorial Assistant, has been a pleasure from our initial discussions, in early 2006, throughout the process to the fi nal submission of the manuscript

Acknowledgments

The author acknowledges and greatly appreciates the

selfl ess efforts of many in the production of this text

First to my wife Allison who has always supported

and encouraged my passion to do the best for my

patients and help other veterinarians do their best too

Next my children Wendi, David, and Lauren who have

helped in the practice and have been there every step of

the journey

Dr Carlos Rice, currently a dental resident at

Univer-sity of Wisconsin, on a four - month volunteer stint at All

Pets Dental in Weston helped catalog thousands of

images from our client base to be considered for

inclu-sion in this text Dr Rice also reviewed the fi nal text

Dr Gary Edelson also volunteered to review the text

word by word multiple times His attention to detail is

much appreciated

Drs Gregg DuPont and Alex Reiter reviewed every

word and image in this text They are expert veterinary

dentists with decades of teaching and practical

experi-ence Both share a passion for the best in companion

animal dental care based on solid peer - reviewed

infor-mation where available Their input resulted in the work

you have before you

little doubt that periodontal disease will either continue

or worsen Plaque control methods must be specifi cally tailored to the patient and client in order to be effective

Through daily use of the oral assessment, treatment, and prevention process, patients can get the best in vet-erinary dentistry, which is our ultimate goal

Although a genuine effort has been made to assure that the dosages and information included in this text are correct, errors may occur, and it is recommended that the reader refer to the original reference or the approved labeling information of the product for addi-tional information Dosages should be confi rmed prior

to use or dispensing of medications

Cats are not dogs Small dogs are plagued primarily

with various degrees of periodontal disease (gingivitis

and periodontitis) Large dogs more commonly present

with gingivitis, fractured teeth, and oral masses Feline

Dentistry: Oral Assessment, Treatment, and Preventative

Care was born primarily to give cats their fair due, a

book on dentistry dedicated solely to their species

Cats also are affected by periodontal disease and

frac-tured teeth, but their main oral pathologies include

tooth resorption, oropharangyeal infl ammation, and

maxillofacial cancer Plaque prevention products and

techniques covered in this text also differ from those

used in dogs

The second goal in writing this text is to introduce to

some and reinforce to others the paradigm shift

elimi-nating the terminology “ doing a dentistry, ” “ performing

a prophy, ” or “ Max is in for a dental ” Replacing the old

terminology with “ oral assessment, treatment, and

pre-vention, ” better represents what we do as veterinary

dentists

Assessment involves evaluation of the patient before

the anesthetic procedure and includes medical and

dental history, feeding management, home oral hygiene,

and physical and laboratory testing Once the patient is

anesthetized, a tooth - by - tooth examination is conducted

to create a treatment plan

Treatment with the goal of eliminating non - functional

abnormalities uncovered during assessment is next The

treatment plan often can be accomplished within one

anesthetic visit In some instances, multiple visits or

life-long therapy are indicated

Prevention of periodontal disease is aimed at

control-ling plaque Prevention is as important as the

assess-ment and treatassess-ment steps Without prevention, there is

FELINE DENTISTRY

Oral Assessment, Treatment, and Preventative Care

Oral Assessment

Section I

nerve The body (the rostral two - thirds) of the tongue is attached ventrally to the midline of the fl oor of the mouth by the lingual frenulum

Tongue

The tongue has important functions in grooming, eating, drinking, and vocalization The tongue is composed of both striated intrinsic and extrinsic muscles The body

of the tongue comprises the rostral two - thirds The root comprises the caudal one - third and is attached to the hyoid apparatus

The dorsal surface of the tongue is covered by ized stratifi ed squamous epithelium that forms papillae The tongue of a cat is populated by fi liform, fungiform, vallate, foliate, and conical papillae Filiform and fungi-form papillae occupy the dorsal surface of the tongue body Vallate papillae separate the tongue body and root dorsally Vallate, foliate, and conical papillae occupy the tongue root (fi gs 1.2 a, b)

Pillars of mucosa and the palatoglossal folds extend

to the soft palate at the base of the tongue (fi g 1.3 ) The ventral tongue surface contains less cornifi ed mucosa The lingual frenulum connects the tongue to the fl oor of the mouth within the intermandibular space

Innervation

Sensory input is received from maxillary and lar divisions of the trigeminal nerve The maxillary branch leaves the trigeminal ganglion, then exits the cranial cavity through the foramen rotundum, courses through the alar canal and the pterygopalatine fossa to enter the infraorbital canal Just before entering the caudal limit of the infraorbital canal, the nerve branches

mandibu-to become the major and minor palatine nerves These nerves innervate the hard and soft palates and the naso-pharynx The palatine nerves are desensitized with the maxillary nerve block

Anatomy

Chapter 1

An understanding and appreciation of feline dental

pathology, treatment, and prevention requires a deep

awareness of the structure and function of oral tissues

that are composed of the teeth and supporting tissues

Oral Cavity

The oral cavity extends from the lips to the pharynx,

bounded laterally by the cheeks, dorsally by the palate,

and ventrally by the tongue and intermandibular tissues

The oral cavity is divided into the oral cavity proper and

the oral vestibule Within the oral cavity proper are

the hard palate, soft palate, tongue, and the fl oor of the

mouth Caudally, the oral cavity proper ends at the

palatoglossal folds The oral vestibule spans between

the lips, cheeks, and dental arches The labial vestibule

is the space between the incisors, canines, and lips The

buccal vestibule is the space between the cheek teeth and

the cheeks (fi gs 1.1 a – g)

Mucosa

Oral mucosa covers the surface of the mouth The outer

layer is composed of variably pigmented nonkeratinized

and parakeratinized stratifi ed squamous epithelium

The submucosa is composed of loose connective tissue,

salivary glands, blood vessels, muscle fi bers,

lymphat-ics, and salivary ducts The submucosa of the palate is

composed of dense collagen

Muscles

The muscles of mastication that close the jaws are the

temporal, masseter, and medial and lateral pterygoid

muscles, all of which are innervated by the mandibular

nerve (the only motor branch of the trigeminal nerve)

The digastricus muscle opens the mouth Its rostral belly

is innervated by the mandibular branch of the trigeminal

nerve, while its caudal belly is innervated by the facial

8 Feline Dentistry

The maxillary arteries also give rise to the major tine arteries, which anastomose with the infraorbital arteries The infraorbital arteries exit at the infraorbital foraminae to supply the rostral muzzle

Lymph from the oral cavity drains into the parotid, mandibular, lateral, and medial retropharyngeal, super-

fi cial, and deep cervical lymph nodes

Salivary Glands

The major salivary glands in the cat include the parotid, zygomatic, mandibular, and sublingual Saliva from the parotid gland exits at a papilla in the alveolar mucosa, just caudal to the maxillary fourth premolar Saliva from the zygomatic gland exits at a papilla in the alveolar mucosa near the maxillary fi rst molar Saliva from the mandibular and sublingual glands enters the oral cavity through the sublingual caruncles located ventral and rostral to the base of the tongue (fi gs 1.4 a, b)

Cats have four molar salivary glands The buccal molar glands empty into the oral cavity through several small ducts The lingual molar glands are located in the membranous molar pad linguodistal to the mandibular

fi rst molar teeth (fi g 1.5 )

Periodontium

The term periodontium is used to describe tissues that

surround and support the teeth, including the gingiva, periodontal ligament, cementum, and alveolar bone

Gingiva The cat ’ s oral cavity is lined with keratinized and non-keratinized stratifi ed squamous epithelium Gingiva refers to the keratinized oral mucosa that covers the alveolar process and surrounds the cervical portion of the tooth crowns Unlike the epithelial lining of the digestive tract, the gingiva does not have absorptive capacity but acts as a physiologic permeable barrier that protects underlying structures (fi g 1.6 )

The gingival epithelium is composed of the following:

• The oral epithelium, also called the outer gingival epithelium, which is keratinized or parakeratinized and covers the oral surface of the attached gingiva and gingival papillae

• The sulcular epithelium is a nonkeratinized sion of the oral epithelium into the gingival sulcus The bottom of the gingival sulcus in a periodontally

exten-The maxillary branch of the trigeminal nerve also

gives off the caudal maxillary alveolar nerve, which

innervates the maxillary fi rst molar, the buccal gingiva,

and mucosa This area is blocked with the infraorbital

nerve block

After giving off the caudal maxillary alveolar nerve,

the maxillary nerve enters the infraorbital canal, where

it is called the infraorbital nerve While the infraorbital

nerve is traversing the infraorbital canal, it gives off two

more branches that exit ventrally from the canal The

middle maxillary alveolar nerve innervates the

premo-lars and associated buccal gingiva The rostral maxillary

alveolar nerve supplies the canines, incisors, and

associ-ated buccal gingiva The remaining fi bers of the

infraor-bital nerve then exit the rostral extent of the infraorinfraor-bital

canal to innervate the lateral and dorsal cutaneous

struc-tures of the rostral maxilla and upper lip The middle

maxillary alveolar, rostral maxillary alveolar, and the

infraorbital nerves are anesthetized by the rostral

infra-orbital nerve block

The mandibular division of the trigeminal nerve arises

from the trigeminal ganglion, exits the cranium via the

foramen ovale, and divides into multiple branches The

divisions include the sensory buccal nerves, lingual

nerve, and mandibular (inferior alveolar) nerve The

buccal nerves receive stimuli from the facial

muscula-ture, skin and mucosa of the cheek, and buccal gingiva

along the caudal mandible

The hypoglossal nerve innervates the tongue, the fl oor

of the mouth, the lingual gingiva, and the mandibular

salivary gland The mandibular nerve enters the

man-dible on the lingual side, via the mandibular foramen

The nerve then courses rostrally within the mandibular

canal to innervate the mandibular teeth to the midline

This nerve can be blocked with the mandibular (inferior

alveolar) nerve block Rostral to the third premolar

tooth, the mandibular nerve gives off mental nerve

branches These branches exit through the mental

foram-ina (rostral, middle, and caudal) and innervate the

cuta-neous areas of the chin and lip, and the rostral buccal

gingiva and mucosa These nerves are blocked with the

mental nerve blocks (usually the middle mental nerve is

blocked)

Blood Supply and Lymphatic Drainage

The external carotid arteries branch off to the maxillary

arteries They further supply the mandibular (inferior

alveolar) arteries, which enter the mandibular foramina

on the medial sides of the mandibles and then course

rostrally in the mandibular canals, where they exit

through the mental foramina

• The junctional epithelium attaches to enamel of the

most apical portion of the crown by means of

hemidesmosomes and lies at the fl oor of the sulcus,

immediately coronal to or at the cementoenamel

junction The junctional epithelium and gingival

connective tissue separate the periodontal ligament

from the oral environment The fl oor of the gingival

sulcus is located on the most coronal junctional

epi-thelial cells

Marginal gingiva is the most coronal (toward the

crown) aspect of the gingiva that is not attached to the

tooth but lies passively against it When healthy, it appears coral - pink, fi rm, and with knife - edged margins Pigment may or may not be normally present The space between the tooth and the marginal gingiva is the gin-gival sulcus (or crevice) The normal depth of the sulcus

is less than 1 mm in cats

The free gingival margin is the coronal edge of the marginal gingiva Marginal gingiva is demarcated from

Figure 1.5 Membranous bulge linguodistal to the mandibular fi rst molar tooth containing a minor salivary gland (lingual molar gland)

10 Feline Dentistry

ment near the apex of the root and from lateral aspects

of the alveolar socket and branch into capillaries within the ligament along the long axis of the tooth Collagen

fi bers also run through these spaces The blood vessels are closer to the bone than to the cementum Venules drain the apex through apertures in the bony wall of the alveolus and into the marrow spaces

Nerve bundles enter the periodontal ligament through numerous foramina in the alveolar bone They branch and end in small rounded bodies near the cementum The nerves carry pain, touch, and pressure sensations and form an important part of the feedback mechanism

of the masticatory apparatus

The periodontal ligament has great adaptive capacity

It responds to chronic functional overload by widening

to relieve the load on the tooth Vascular tions between the pulp and periodontium form pathways for transmission of infl ammation and micro-organisms between the tissues

Cementum Cementum covers the root and provides attachment for the periodontal ligament Cementum is produced con-tinuously, slightly increasing in thickness throughout life Acellular cementum is present at the coronal one - third of the root Cellular cementum is present at the apical two - thirds of the root It is capable of formation, destruction, and repair It is avascular but is nourished from vessels within the periodontal ligament Cemento-cytes in cellular cementum communicate with each other via canaliculi and with underlying dentin

Alveolar Bone Alveolar processes house the alveoli, which support the teeth by providing attachment for fi bers of the periodon-tal ligament An alveolus can be divided into two parts:

1 Alveolar bone proper, which is a thin layer of bone surrounding the root and allowing attachment to the periodontal ligament

2 Supporting alveolar bone, which consists of compact, cortical, or cancellous bone on the vestibular and oral aspects of the alveolar process

The alveolar bone and cortical plates are thickest in the mandible The shape and structure of the trabeculae

of spongy bone refl ect the stress - bearing requirements

of a particular site In some areas, alveolar bone is thin with no spongy bone The alveolar bone proper is also referred to as the cribriform plate and is identifi ed on radiographs as lamina dura (fi g 1.10 )

The alveolar bone height is an equilibrium between bone formation and bone resorption When bone

the attached gingiva by the gingival groove, a slight

depression on the gingiva corresponding to the normal

sulcus depth (fi g 1.7 )

In the cat, the healthy free gingival margin of

premo-lars and mopremo-lars lies between 0.5 and 1 mm coronal to the

cementoenamel junction, where root cementum meets

crown enamel

The attached gingiva is located apical to the marginal

gingiva and is normally tightly bound to the periosteum

of alveolar bone Attached gingiva is keratinized to

withstand the stress of mastication The width of the

attached gingiva varies in different areas of the mouth

The attached gingiva is widest at the maxillary canines

The fi rmly attached gingiva is contiguous with loose

alveolar mucosa at the mucogingival junction, also

referred as the mucogingival line The mucogingival

junction remains stationary throughout life, although

the gingiva around it may change in height due to

attachment loss (fi gs 1.8 a, b)

The gingival sulcus is a shallow space between the

marginal gingiva and the tooth The sulcus depth is

generally under 1 mm but varies depending on the

spe-cifi c tooth and the size of the cat In cases of periodontal

disease, the abnormal sulcus is termed a pocket, which

extends further apically due to destruction of the

peri-odontium (fi gs 1.9 a, b)

Periodontal Ligament

The periodontal ligament is a dense, fi brous connective

tissue that attaches the tooth root to the bony alveolus

The periodontal ligament also acts as a suspensory

cushion against occlusal forces and as an epithelial

attachment to keep debris from entering deeper tissues

The blood supply to the periodontal ligament

origi-nates from the alveolar artery Arterioles enter the

Figure 1.7 Gingival structures surrounding the left maxillary fourth

premolar

Facium The facial part of the skull, which encloses the nasal and oral cavities, is divided into oral, nasal, and orbital regions The oral region surrounding the oral cavity is composed of the incisive, maxillary, palatine, and man-dibular bones

The region surrounding the nasal cavity is composed

of the nasal, maxillary, palatine, and incisive bones The orbital region is formed by the frontal, lacrimal, palatine,

Figure 1.12 a Left lateral aspect of

the skull with the zygomatic arch

removed; 1 Parietal bone; 2 Squamous

temporal bone; 3 Sphenopalatine

foramen; 4 Maxilla; 5 Incisive bone; 6

Frontal bone; 7 Lacrimal bone; 8 Optic

canal

b Medial aspect of a sagittal section

of the left aspect of the skull: 1 Incisive

bone; 2 Maxilloturbinates; 3 Nasal

bone; 4 Nasal septum; 5 Palatine bone;

6 Pterygoid bone; 7 Ethmoid bone

c Dorsal aspect of the skull: 1 Incisive

bone; 2 Nasal bone; 3 Maxilla; 4

Frontal bone; 5 Zygomatic process of

frontal bone; 6 Zygomatic bone; 7

Pari-etal bone; 8 Zygomatic process of

tem-poral bone; 9 Lacrimal foramen; 10

Infraorbital foramen

d Ventral aspect of the skull: 1

Inci-sive bone; 2 Palatine process of the

maxilla; 3 Major palatine foramen; 4

Vomer bone; 5 Pterygoid bone; 6 Frontal

bone; 7 Palatine bone; 8 Temporal

process of the zygomatic bone; 9

Zygo-matic process of the temporal bone; 10

Retroarticular process; 11 Mandibular

fossa of the articular surface of the

tem-poromandibular joint (Images reprinted

with permission of Morton Publishing

Company.)

The maxillary bones or maxillae form the lateral parts of

the face and the part of the hard palate that holds the

canine and upper cheek teeth The maxilla articulates

with the incisive bone rostrally, the nasal bone dorsally,

the vomer bone medially, and the lacrimal and

zygo-matic bones caudally (fi gs 1.13 a, b)

The palatine bone forms the bony part of the hard

palate together with the maxillary and incisive bones

The incisive bone located rostrally holds the upper

inci-sors A pair of openings, the palatine fi ssures, allows

passage of the incisive ducts of the vomeronasal organ

The incisive papilla located just caudal to the maxillary

fi rst incisor teeth houses these incisive ducts as they

open into the oral cavity (fi gs 1.14 a, b)

The hard palate separates the oral and nasal cavities

The primary palate is the incisive portion of the palate

and associated soft tissues The secondary palate includes

the remaining hard and soft palatal structures Firmly

attached, heavily keratinized mucosa covers the hard palate Seven to eight transverse ridges called rugae pro-trude from the mucosa with rows of papillae between the ridges The soft palate begins caudal to the maxillary

fi rst molar teeth and separates the nasopharynx dorsally and oropharynx ventrally (fi gs 1.15 a, b)

The infraorbital canal is located apical to the maxillary third and fourth premolars below the orbit Compared

to the dog, the cat ’ s infraorbital canal is shorter and usually less than fi ve millimeters in diameter

Mandibles The large bones articulating with the skull that support the lower teeth are the mandibles Each mandible is composed of a horizontal body and a vertical ramus The body supports the lower teeth The ramus has three processes: coronoid, condylar, and angular The condy-lar process articulates with the cranium in the temporo-mandibular joint (fi gs 1.16 a – c)

The mandibles are connected to each other by a strong

fi brocartilaginous joint at the mandibular symphysis The nerves and vascular supply to the mandibular teeth

Anatomy 15

a

b

Figure 1.13 a Lateral aspect of right maxilla: 1 Alveolar process; 2 Frontal

process; 3 Infraorbital canal; 4 Zygomatic process b Medial aspect of the

right maxilla: 1 Maxillotubinates; 2 Palatine process

a

b

Figure 1.14 a Palatine fi ssures b Incisive papilla

enter the mandibular canal ventrally on the lingual

aspect of the angle of the mandible and course rostrally

exiting at the caudal, middle, and rostral mental

foram-ina to supply the rostral mandible, chin, lip, buccal

gingiva, and mucosa (fi gs 1.17 a – c)

The tongue and some of the muscles of the hyoid

apparatus occupy the intermandibular space

Temporomandibular Joint The head of the condylar process of the mandibular ramus articulates with the base of the zygomatic process

of the squamous part of the temporal bone (mandibular fossa) at the temporomandibular joint: a transversely elongated (cigar - shaped), condylar, synovial joint (fi g 1.18 ) The retroarticular process is a caudoventral exten-sion of the mandibular fossa The retoarticular process helps prevent caudal luxation of the mandible (fi g 1.19 ) The insertion of the masseter muscle reaches the ventral and rostral aspect of the joint capsule There is a thin, cartilaginous intra - articular disc dividing the joint into dorsal and ventral compartments This disc reduces friction by providing a double synovial fi lm

Teeth

Dental Formula Normally, there are twenty - six deciduous and thirty permanent teeth in the cat ’ s oral cavity

Dental formulas (upper number indicates the lary teeth, lower number the mandibular teeth) are as follows:

a

b

Figure 1.15 a Sagittal section of dissected head: 1 Choana; 2 Nasopharynx;

3 Epiglottis; 4 Palatine tonsil in tonsilar fossa; 5 Oropharynx; 6 Oral cavity;

7 Hard palate b Roof of the oral cavity, 1 Hard palate, 2 Palatine rugae, 3 Palatine tonsil, 4 Stick in nasopharynx, 5 Epiglottis (refl ected laterally) 6 Pala- toglossal arch, 7 Soft palate

Figure 1.17 a Mandibular symphysis dorsal view b Mandibular symphysis rostral view showing the mental foramina (arrows) c Mental foramina

Man-Anatomy 19

Incisors are small teeth located between the canines

They are used for prehension Incisors are referred to

as right/left, maxillary/mandibular, fi rst, second, and third incisors (fi g 1.20 )

When using the modifi ed Triadan system, right lary incisors are numbered 101, 102, and 103 starting from the fi rst incisor, and left maxillary incisors are numbered 201, 202, and 203 The left mandibular inci-sors are numbered 301, 302, 303, and the right mandibu-lar incisors are 401, 402, 403 (fi g 1.21 )

Canines are single - rooted teeth located rostrally in the

mouth caudolateral to the incisors They are used for piercing and biting Canines are referred to as right/left, maxillary/mandibular canines The crowns of the max-illary and mandibular canine teeth have vertical grooves (fi gs 1.22 , 1.23 )

When using the modifi ed Triadan system, the right and left maxillary canines are numbered 104 and 204, respectively The root and crown of the maxillary canines help to hold the upper lip outward, so that when the mouth is closed, the coronal tip of the mandibular canine

All of the incisors and canine teeth have one root The

maxillary second premolar, if present, normally has one

root; however, studies have shown nearly 40% of the

maxillary second premolars have two (sometimes fused)

roots The maxillary third premolar has two roots in

most cases (10% of the maxillary third premolars have a

small third root), and the maxillary fourth premolars

have three roots The maxillary fi rst molars, if present,

usually have two roots

The mandibular cheek teeth in a cat (third and fourth

premolars and fi rst molars) have two roots

Tooth Types

Teeth are categorized by location and form There are

four types of teeth in the cat:

Figure 1.20 Maxillary and mandibular incisors

Anatomy 21

Premolars are located caudal to the canines There are

normally three maxillary and two mandibular lars in the cat Proper nomenclature of feline premolars

premo-is based on the archetypal carnivore model, which has

a full dentition of forty - four teeth (six incisors, four canines, sixteen premolars, and twelve molars)

The premolar behind the maxillary canine is termed the right or left maxillary second premolar (fi g 1.26 ) Using the modifi ed Triadan system, the second premo-lars are referred to as tooth 106 (right) or 206 (left) The second premolar has one or two fused roots The third premolars (107, 207) have two roots The fourth premo-lars (108, 208) have three roots (mesiobuccal, mesiopala-tal, and distal)(fi g 1.27 )

The premolar behind the mandibular canine is termed the left or right mandibular third premolar (307, 407),

slides into the vestibule without traumatizing the upper

lip The left and right mandibular canines are numbered

304 and 404, respectively (in the modifi ed Triadan

system, all the canines end in 4 and fi rst molars in 9)

22 Feline Dentistry

followed by the fourth premolar (308, 408), which has

two roots (fi gs 1.28 a, b)

Molars are located caudal to the premolars There is

one set in the maxilla termed right or left maxillary fi rst

molar (109, 209) and one set in the mandible termed left

or right mandibular fi rst molar (309, 409) The

mandibu-lar fi rst momandibu-lar has one mandibu-large mesial root and a smaller

distal root, which angles caudally (fi gs 1.29 , 1.30 a – d)

Tooth Composition

The exterior surface of the healthy crown is covered with

a thin layer of enamel, a hard inorganic substance (96%

inorganic) formed by ameloblasts within the tooth bud

before eruption Enamel when damaged is incapable of

repair once the tooth has erupted

Dentin located beneath the enamel and cementum

composes the majority of the mature tooth mass Dentin

is a specialized connective tissue of mesenchymal origin

and is the second hardest tissue in the body after enamel

It is 70% inorganic and 30% organic (water, collagen,

and mucopolysaccharide)

a

b

Figure 1.28 a Teeth of the lower jaw b Right mandibular premolars Figure 1.29 Dissected left mandibular fi rst molar

Dentin is porous; each square millimeter contains over 40,000 dentinal tubules that communicate between the pulp and the dentin - enamel or dentin - cementum junctions If there is near - pulp exposure from trauma or resorption, bacteria can travel through the exposed den-tinal tubules to the pulp Near exposure can also trans-mit painful stimuli (heat, cold, pressure) from the oral environment to the pulp

In cats and other species including the dog, two scopic features of the dentin known as vasodentin and osteodentin may occasionally exist Vasodentin is char-acterized by microscopic vascular inclusions within the outer third of the dentin It is found to have vascular channels and dentinal tubules coursing through vaso-dentin randomly Osteodentin, unlike vasodentin, is most often found in the dentin adjacent to the root canal Previous studies have demonstrated the presence of these two peculiar microscopic structures in cats with tooth resorption However, vasodentin and osteodentin have also been found in teeth free of resorption, making

micro-a cmicro-ause - micro-and - effect relmicro-ationship diffi cult to confi rm The pulp, located in the center of the tooth, is com-posed of connective tissue, nerves, lymph and blood vessels, collagen, and odontoblasts, which form dentin throughout the tooth ’ s life The pulp cavity consists of a pulp chamber located in the crown and a root canal in

Figure 1.30 a Modifi ed Triadan system numbering of teeth in the upper jaw b – d Modifi ed Triadan system numbering of teeth in the lower jaw

the root In a fully mature tooth, an apical delta

contain-ing minute opencontain-ings allowcontain-ing the passage of vessels and

nerves is present at the root apex Occasionally, there are

communication canals present at the furcation of the

maxillary fourth premolar and other multirooted teeth

(fi g 1.31 )

During pre - eruptive development and during

erup-tion, the odontoblasts produce primary dentin Once the

tooth has developed to its fi nal length, the odontoblasts

produce secondary dentin, causing the dentinal walls to

thicken toward the pulp cavity This will effectively decrease the width of the pulp cavity as the cat ages

Reparative or tertiary dentin is produced in response to

thermal, mechanical, occlusal, or chemical trauma to the odontoblasts The pulp chamber in cats lies closer to the enamel than in dogs For this reason, any tooth fracture

24 Feline Dentistry

Figure 1.31 Illustration of sagittal section through the canine tooth

in the cat should be treated aggressively, since most

require endodontic therapy or extraction

Odontoblast processes extend into the dentinal

tubules These processes, together with the fi ne nerve

endings, cause the dentin to be sensitive to temperature

and pressure When traumatized, the pulp reacts to

irri-tants through infl ammation If untreated, severe infl

am-mation spreads up and/or down the pulp, eventually

becoming irreversible Toxic products from damaged

tissue and microorganisms in the tissue sustain

infl ammation

The tooth ’ s anatomical crown is visible to the naked

eye The root is located in the alveolus encased in the

alveolar processes beneath the gingiva The cribriform

plate (lamina dura) lines the alveolus (fi g 1.32 )

Tooth Eruption

The maxillary teeth generally erupt before their

man-dibular counterparts Eruption of the incisors precedes

that of the canines, which is later followed by the

pre-molars and pre-molars

The deciduous tooth eruption is normally complete by two months of age By seven months, the permanent teeth should be fully erupted (Table 1.1 )

Terminology

Teeth

Incisors are referred to as the (right or left, maxillary or

mandibular) fi rst, second, or third incisors numbered from the midline

In the cat, the tooth immediately distal to the

maxil-lary canine is the second premolar ; the tooth

immedi-ately distal to the mandibular canine is the third premolar

Surfaces of teeth and directions in the mouth ( fi g 1.33 )

Vestibular is the correct term referring to the surface of the tooth facing the vestibule or lips; buccal and labial

are acceptable alternatives

Anatomy 25

Periodontal ligament Apical delta

Cementum

Alveolar mucosa Mucogingival line Attached gingiva Free gingiva Gingival sulcus

Dentin

Enamel Pulp

Epithelial attachment

Gingival margin Alveoler crest

Cortical plate

Alveolar process Lamina dura Trabecular bone

Figure 1.32 Canine tooth and surrounding structures

Table 1.1. Approximate age when teeth erupt (in weeks)

The surface of a mandibular or maxillary tooth facing

the tongue is the lingual surface Palatal can also be

used when referring to the lingual surface of maxillary teeth

Mesial and distal are terms applicable to tooth

sur-faces The mesial surface of the fi rst incisor is next to the median plane; on other teeth it is directed toward the

fi rst incisor The distal surface is opposite the mesial surface

Figure 1.33 Directions in the oral cavity

Anatomy 27

Rostral and caudal are the positional and directional

anatomical terms applicable to the head in a sagittal

plane in nonhuman vertebrates Rostral refers to a

struc-ture closer to, or a direction toward the most forward

structure of the head Caudal refers to a structure closer

to, or a direction toward the tail

Jaws

All mammals have two maxillas (or maxillae) and two

mandibles The adjective maxillary is often used in a

wider sense, for example, “ maxillary fractures ” to

include other facial bones, in addition to the maxillary

bone proper

Further Reading

American Veterinary Dental College Veterinary dental

nomen-clature (available at www.avdc.org )

Bishop MA , Malhotra M An investigation of lymphatic vessels

in the feline dental pulp Am J Anat 1990 ; 187 : 247 – 253

Crossley DA Tooth enamel thickness in the mature dentition

of domestic dogs and cats: preliminary study J Vet Dent

1995 ; 12 : 111 – 113

Floyd MR The modifi ed Triadan system: nomenclature for

veterinary dentistry J Vet Dent 1991 ; 8 ( 4 ): 18 – 19

Gioso MA , Carvalho VGG Oral anatomy of the dog and cat in

veterinary dentistry practice Vet Clin North Am Small Anim

Pract 2005 ; 35 : 763 – 780

Gracis M Radiographic study of the maxillary canine tooth of

four mesaticephalic cats J Vet Dent 1999 ; 16 : 115 – 128

Gracis M Orodental anatomy and physiology In: Tutt C ,

Deeprose J , Crossley D (eds) BSAVA Manual of Canine and

Feline Dentistry , 3rd ed BSAVA , Gloucester , 2007 ; 1 – 21

Harvey CE Anatomy of the oral cavity in the dog and cat

Veterinary Dentistry , WB Saunders , Philadelphia , 1985 ;

5 – 22

Harvey CE , Emily PP Function, formation, and anatomy of

oral structures in carnivores, Small Animal Dentistry, Mosby,

St Louis, 1993 ; 1 – 18

Hayashi K , Kiba H Microhardness of enamel and dentine of cat premolar teeth Nippon Juigaku Zasshi (Japanese Journal

of Veterinary Science) , 1989 ; 51 : 1033 – 1035 Hennet P Dental anatomy and physiology of small carnivores

In: Crossley DA , Penman S (eds) BSAVA Manual of Small Animal Dentistry , 2nd ed BSAVA , Cheltenham , 1995 ;

93 – 104 Hennet PR , Harvey CE Apical root canal anatomy of canine teeth in cats Am J Vet Res 1996 ; 57 : 1545 – 1548

Holland GR The dentinal tubule and odontoblast process in the cat J Anat 1975 ; 120 : 169 – 177

Hudson LC , Hamilton WP Atlas of Feline Anatomy for erinarians WB Saunders , Philadelphia , 1993

Nanci A Ten Cate ’ s Oral Histology, Development, Structure, and Function, 6th ed Mosby, St Louis, 2003

Negro VB , Hernandez SZ , Maresca BM , Lorenzo CE Furcation canals of the maxillary fourth premolar and the mandibular

fi rst molar teeth in cats J Vet Dent 2004 ; 21 : 10 – 14 Okuda A , Inoue E , Asari M The membraneous bulge lingual

to the mandibular molar tooth of a cat contains a small vary gland J Vet Dent 1996 ; 13 : 61 – 64

Orsini P , Hennet P Anatomy of the mouth and teeth of the cat Vet Clin North Am Small Anim Pract 1992 ; 22 : 1265 – 1277

Rosenzweig LJ Anatomy of the Cat Brown Publishers , Dubuque ,

1993

Schaller O Illustrated Veterinary Anatomical Nomenclature , 2nd

ed Enke Verlag , Stuttgart , 2007

Verstraete FJM Colour Self - Assessment Review of Veterinary tistry Manson , London , 1997

Verstraete FJM , Terpak CH Anatomical variations in the tion of the domestic cat J Vet Dent 1997 ; 14 : 137 – 140 Vongsavan N , Matthews B The vascularity of dental pulp in cats J Dent Res 1992 ; 71 : 1913 – 1915

Wiggs RB , Loprise HB Oral anatomy In: Veterinary Dentistry: Principles and Practice Lippincott - Raven , Philadelphia 1997 ,

55 – 86 Wilson G Timing of apical closure of the maxillary canine and mandibular fi rst molar teeth of cats J Vet Dent 1999 ; 16 :

19 – 21

of the examiner Some cats are too fractious or painful

to inspect without chemical restraint

After a general physical examination, concentrate on the head and face Signs of facial asymmetry, differences

in palpebral sizes, ocular or nasal discharge, discomfort

or swelling, pain on palpation, or discoloration should

be noted (fi gs 2.1 a – g)

While looking in the cat ’ s eyes, palpate along the dibles and maxillae Enlarged unilateral or bilateral mandibular lymph nodes should be noted if present during this examination Holding the head steady in one hand, the rostral portion of the lips is pulled caudally to examine occlusion; missing, extra, or malpositioned teeth; the presence of periodontal disease or oral masses; and fractured, discolored, or resorbed teeth The man-dibular third premolar, often the fi rst tooth affected by tooth resorption, is diffi cult to observe unless you move the lower lip ventrally (fi gs 2.2 a – i and 2.3 a, b)

During the conscious patient examination, the mouth

is opened and closed to evaluate temporomandibular joint movement To open a cat ’ s mouth, place one hand

on top of the cat ’ s head with the thumb and forefi nger lightly pressing just behind the lip commisures Pull the lips caudally to reveal the premolars Tilt the head back-ward while applying the forefi nger of the opposite hand

to the mandibular incisor area, pulling the lower jaw ventrally (fi g 2.4 )

Pain, crepitus, and decreased ability to open or close the mouth are noted on the medical record

Generally, a scissors bite with the maxillary incisors touching and located slightly rostral to the mandibular incisors is considered normal in domestic short hair cats and a majority of the recognized cat breeds In brachycephalic breeds (Burmese, Himalayan, and Persian), mandibular mesioclusion, where the maxillary incisors are positioned caudal to their mandibular counterparts, is abnormal but considered “ normal occlusion ” for the breed Mandibular distoclusion, where the maxillae extend far in front of the mandibles,

is not considered normal in any cat breed (fi gs 2.5 , 2.6 , and 2.7 )

Oral Examination

Chapter 2

Treatment planning is based on the results of clinical

examination and diagnostic imaging with direction

from patient history and dental habits The best possible

treatment outcome is related to an accurate diagnosis

Using a carefully planned examination, the practitioner

can recognize both normal and abnormal conditions A

permanent record should be made of relevant medical

and dental history and diagnostic data, as well as

treat-ment recommended, performed, and advised for the

future

Patient History

Patient history is an important part of the assessment

process Relevant history should include present and

past medical information, vaccination status, amount of

time spent indoors and outdoors, and information about

other animals in the patient ’ s environment Discussion

of clinical signs related to oral disease in the cat should

include diffi culty with prehension; diffi culty with

chewing and/or swallowing food; pawing at the mouth;

periodic pain with vocalization when chewing, opening,

or closing the mouth; increased salivation with or

without hemorrhage; sneezing; nasal discharge; facial

swelling; ocular signs; and decreased self - grooming

The intake discussion should include dialogue with

the owner concerning their wishes and perception of

type and level of service they are expecting to receive

Additionally, the willingness of the client to provide

home care, as well as the acceptance of home care

pro-cedures by the patient, should be addressed in order to

help construct a treatment plan

Examination of the Conscious Cat

Most cats will allow an initial evaluation of their teeth

and oral cavity when approached in a slow and gentle

manner The extent of an examination on a nonsedated

cat is dependent upon patient cooperation and expertise